If You’re Not Using Python DATA CLASSES Yet, You Should 🚀

This video is a tutorial about Python's dataclasses. I take you through an example that shows what you can do with them. Python data classes are - as you'd expect - in particular suitable to model classes that represent data, and as such they offer easy mechanisms to initialize, print, order, sort, and compare data.
Note that although I'm using a sort_index attribute, strictly speaking that's not needed in this case, because a data class uses a tuple of its attributes in the class definition as the default for sorting. I'm not a fan of this kind of hidden behavior, so I prefer to do it explicitly (using something that is called sort_index in this case). Another advantage of using a separate field, is that you can do more complicated ordering, using for example a weighted combination of age and strength.
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Some interesting links:
- realpython.com/python-data-cl...
- Frozen instances: docs.python.org/3/library/dat...
- If you want to go 'next-level' with dataclasses, check out Pydantic (pydantic-docs.helpmanual.io/). Pydantic enforces type hints at runtime, and offers a really nice extension for data validation.
- The code from this video is available here: github.com/ArjanCodes/2021-da...
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🔖 Chapters:
0:00 Intro
0:33 Behavior-driven vs data-driven classes
2:11 Explaining the example
3:31 Creating a dataclass
4:37 Sorting and comparing
6:58 Default values
7:40 Creating read-only (frozen) objects
8:55 String representation of data
9:34 Final thoughts
#arjancodes #softwaredesign #python
Thumbnail photo background by Markus Spiske: unsplash.com/@markusspiske
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[@ArjanCodes]

Anybody else into The Witcher?

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If you talking about the game, I bought it on gog but never got the chance to install it. Too much time fighting with k8s manifests and no time for playing :c

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I have the Witcher 3 for the Playstation lying in a drawer, haven't gotten around to that either.

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@@ArjanCodes I have the Witcher 3 also lying in a drawer but mine is for the xbox :D

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[@falak88]

Just in case you're feeling low Arjan, you are doing a freaking great job here. Thank you very much ! Keep them coming :D

[@ArjanCodes]

Thank you so much for your kindness, much appreciated! I’m happy you like the videos.

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[@drymanic]

One cool thing about the "frozen" attribute is that if set to True, Python will automatically create a ___hash___ function for your dataclass, allowing it to be used in things like dictionary keys and sets. (Note that if the class contains an unhashable field such as a list, the ___hash___ function will throw an exception).

[@CodingEntrepreneurs]

This is great! Thanks for sharing Arjan. Love your work.

[@jayeshdeorukhkar4956]

Love your videos too 🔥

[@dennissmith6867]

This is a really great intro to data classes, very clear and to the point. Looking forward to more videos like this!

[@ArjanCodes]

Glad you liked it, Dennis!

[@JohnMitchellCalif]

Incredibly clear presentation. I've been programming Python for 25 years and hadn't used data classes. Thanks! Subscribed.

[@jakefischer8281]

I believe it is fairly new to python

[@jimmy21584]

When dealing with data in Python these days, I find myself almost exclusively doing comprehensions and functional programming with dictionaries and lists, rather than using classes. But good to know this is out there.

[@ZergD]

I concur with that!

[@AddyVDH]

This is the best way IMO. Heavy OOP often makes python code super messy as many people get involved in a codebase.

[@bakane6030]

@@AddyVDH Agreed. Python is NOT supposed to be an object oriented language

[@nsambataufeeq1748]

I had a graduate class in LISP, i found the functional bits interesting and are now using them in python

[@JustMaiyak]

FP un Python feels great !

[@myce-liam]

Arjan, your videos are really clear and simple. You are very much appreciated. Greetings from the UK!

[@ArjanCodes]

Thanks so much Liam, glad the content is helpful!

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Where is 'love' button? 'Like' is not an accurate reflection of what I feel about your videos. I've seen many amazing dudes with online tutorials on KZbin, but you are the most amazing

[@typehint]

Really happy I found your channel! You and Corey Schafer are my two favourites for learning Python right now. Keep up the excellent work!

[@ArjanCodes]

Thanks so much Finah.

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Very straightforward and nice way of explaining how it all works.

[@Egon3k]

Everytime watching one of your videos, I learn something new. Keep on going with these very nice and easy to understand videos :)

[@mithunmanoharmithun]

I would love to see a complete python course taught by Arjan!

[@niveshsanghvi9066]

Nice video Arjan ! Looks very useful

[@Yassou1985]

Arjan keep doing your video man ! Your are a true teacher, everthing you say is just so clear. Thank you for your help :)

[@ArjanCodes]

I'm glad my content has been helpful! Thank you for the kind words :)

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This is amazing! I’ve been struggling with my project and this totally saved my day!

[@ArjanCodes]

Glad I could help, Elvis!

[@talhaamir9023]

I loved the start of the video :) This channel deserves a million subs,the only channel most quality content :)

[@kruceo]

Clearly demonstrated. Earned my “like and subscribe”! Looking forward to checking out your other tutorials/content.

[@ArjanCodes]

Thank you Marcel - glad you liked the content!

[@estevaoyt]

Arjan, you are great inspiration, love your videos!

[@ArjanCodes]

I'm happy to hear you have been enjoying the videos!

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I LOVE U, THIS IS THE FIRST STEP FOR UNDERSTAND FAST API AND PYDANTIC, THANK U FOR URS VIDEOS

[@python_byte]

Just loving all of your videos man, keep up the awesome work. My focus is to watch ALL THE VIDEOS

[@ArjanCodes]

Thanks, glad you like the videos!

[@DanielRios549]

This is something I was wondering to use in Python since I discovered that in PHP 8, you do not need to set the construct parameter to attributes anymore, you set the attributes directly on the parameter, this is very useful when you have a lot of initial parameters, pass the parameter and after that set it to an attribute is so so boring

[@justchary]

Very good! Thank you. You really have a talent to explain things

[@ldebrotb09]

Thank you Arjan! Your videos about how to make more of Python (with built-in functions), write better and cleaner code, etc. motivate me in trying to become more Pythonian.

[@ArjanCodes]

Glad to hear they’re helpful to you, Lucien!

Awesome tutorial bro! I had used data classes but this is much more details that I didn’t know about. Thanks

[@ArjanCodes]

You’re welcome- glad you enjoyed it!

[@sf-spark129]

I've been using the conventional class in Python. This is such a great knowledge boost!!

[@patrikwiklund6154]

Arjan. I really appriciate your videos! Thank you! Really awesome

[@ArjanCodes]

My pleasure, Patrik!

[@letsaram]

I love how wisely you avoid all the issues I've had with other peoples code.

[@rupeshchoudhary9237]

Great job. I love you explaining style.

[@ArjanCodes]

Glad you enjoyed it!

[@cetilly]

Awesome! Coming from a C# background this really makes my day to know data classes are a thing in Python. Awesome. Really good video. Thanks Now I need to refactor all my custom data classes :-D

[@ArjanCodes]

It seems technical debt never really stops 😊.

[@christopherc4526]

Just found your channel and I am glad I did. Outstanding introduction to very useful concepts. Well done

[@ArjanCodes]

Awesome, thank you!

[@theophilegaudin2329]

I started using classes when I could not do otherwise. My fonctions had like 15 variables that I had to state explicitly. It was impractical. My code was working on molecules and mixtures of molecules. So I created a class "mixture" and a class "molecule" and suddenly my fonctions were acting on mixtures and molecules rather than long lists of variables. That was such a relief. Now my classes have like 70 attributes because, well, mixtures and molecules have many structural features and properties. Everytime I extend my code I simply add new attributes and that's it.

[@pippog88]

Hands dowm the best tutorials on Python! Thanks for what you're doing! :)

[@ArjanCodes]

Thank you so much!

[@crosby3108]

This was amazing thanks for going into so much detail

[@ArjanCodes]

Thanks - glad you liked it!

[@matthewbailey3052]

Very useful, thanks!

[@glebsidorov9647]

Thanks for the class Mr :)

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Amazing! Thank you for creating this content!

[@ArjanCodes]

Glad you enjoy it!

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Thanks, great job!

[@Xaminn]

Damn. This information is going to save me years of time and frustration. Thanks for this.

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Thank you sir for this video! It was very helpfull for me.

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Loved this!

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These are EXCELLENT videos.

[@skyletwings5711]

8:43 "So frozen helps you to make sure the data is not changed anywhere in your code." ... right after bypassing this mechanism and showing how the data is changed in the code. :D Great videos, you are my no. 1 python instructor. Programming python itself is fun, but learning from a patient, calm, well explaining teacher is invaluable, but free. Thank you for sharing!!

[@thatinstant]

Wow! This video was super helpful in getting familiar with data classes! Great intro! ...Subscribed!

[@ArjanCodes]

Awesome! Thank you!

[@aar021]

That intro was hilarious. Well put video. Super clear.

[@ArjanCodes]

Glad you liked it Alvaro!

[@AdityaDiwakarVex]

Video quality is insanely good for only 8K subscribers. Keep it up!

[@ArjanCodes]

Thanks, will do!

[@Mjuziks]

it was very useful, thanks

[@tuxhome3686]

Great video! I learned a lot.

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Long since I subscribed. 😊 This is quite the top notch content.

[@ArjanCodes]

Thank you so much!

[@Noah-hi2up]

This is a really cool feature and definitely useful for my work! Are data classes actually implemented differently at the c level or is this just a shorthand format for accessing commonly used features?

[@AJ-et3vf]

Awesome video! Thank you!

[@ArjanCodes]

You're welcome AJ!

[@techcode_man]

Just awesome!! Thank you

[@ArjanCodes]

You're welcome!

[@fabulousfabio8228]

Thanks for the video. I just learnt something!

[@ArjanCodes]

Glad it was helpful!

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I find the content of your videos are on the edge of my python knowledge. When I watch one, I learn something new, without it making my brain hurt!

[@ArjanCodes]

That's a good way to put it! Ahah, I'm glad you're enjoying the content!

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Fantastic video, thank you

[@ArjanCodes]

Thanks so much!

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Great video. Thanks for sharing.

[@simplepycodes]

Perfect. Thank you.

[@ArjanCodes]

Thanks so much, glad you liked it! :)

[@TommyReady]

Great video, I learned something.

[@ArjanCodes]

Glad to hear it, Tommy!

[@sami3592]

Another great video. Thanks a lot.

[@ArjanCodes]

You’re welcome, glad you liked it!

[@nlight8769]

I've been coding for... hmm... since python 2.5 as an amateur, when I need it. The vast majority of what I learned is from back then, and while i've been keeping learning, in the last years, besides some modules here and there, I've not learned many new things... discovered the chanel last week, and man I've learned so much since ! Sure there are few design pattern that I was already doing out of pure logic and commodity, though even then the knowledge acquired here have allowed me to refine these to the next level (or on the road to it), plus the terms that goes with it ! Thank you so much ! And there are many new neat things that I've been missing, like the module abstractclass or this dataclass. A great channel : advanced and intermediate concepts, in python !

[@ArjanCodes]

Thank you, I'm happy you like the content!

[@fl4tcircl3]

Thank you sir, brilliant!

[@ArjanCodes]

Glad it was helpful!

[@diogosilva3152]

I have been programming in Python for quite some time now, and I had no idea of this functionality. Thanks :p

[@maverick3069]

This was so cool!

[@ArjanCodes]

Thank you!

[@marcelohpinheiro]

Thanks for your video!

[@ArjanCodes]

You’re welcome!

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Nice video, man! I like your videos.

[@ArjanCodes]

Thanks! Glad you like them.

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Great work...

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love ur work thanks please continue we need you

[@ArjanCodes]

Thank you so much! No worries, I will :).

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Amazing ! Love it, share it.

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You are my python role model

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I really like this! It feels like modern python is much more robust and can be better self-documented and typed nowadays.

[@ArjanCodes]

You might also like Pydantic. It’s very similar but adds a few extras like data validation and nested models. It is a third-party package though.

[@ikustudies]

you're making me rethink my entire codebase. i wish i could start over now but i'm so far. sheesh

[@VorpalForceField]

very cool .. Thank You for sharing

[@ArjanCodes]

Thanks for watching!

[@coriariasgibert9945]

Thanks 😃 great video !

[@ArjanCodes]

Glad you liked it!

[@retrofutur1st]

10/10 video, subscribed and liked 😀

[@ArjanCodes]

Thank you, glad you liked it!

[@martindu9083]

good video, for sort , dataclass will use all attributes by order for checking, so sort_index is not mandatory, its effected just because its the first one

[@qrubmeeaz]

Best Python videos in the known universe!!

[@ArjanCodes]

Thank you so much!

[@drheaddamage]

It's funny that the main touted advantage of Python is that it's got dynamically typed variables. And now the first thing the seasoned programmer does is *hammer those variables down to be a single type to avoid issues further down the road* 😁

[@GJ22]

All of your videos are still a little above my aptitude, I'm still relatively new to coding in general but I feel jumping in at the deep end can sometimes be good 👍

[@Newascap]

Amazing Friday start, thanks for uploading

[@ArjanCodes]

Hope you enjoyed it!

[@Newascap]

@@ArjanCodes Already on your final thoughts. Learned a new decorator and definitely will apply to my projects from now on.

[@andrewiglinski148]

Dude I'm a pretty experienced developer but brand new to python as of 2 months ago... I've seen like 5 videos on dataclasses by now and this is the first one that actually showed the benefits over regular classes... after by mile long init function is finished lol

[@juliennel6939]

great video! thank you 🙏

[@ArjanCodes]

Thank you very much! Glad you liked it!

[@kyletech4878]

I find the asdict and astuple methods from the dataclass library very handy.

They are, I often use asdict to convert a dataclass to JSON :)

[@MohAmuza]

Its an amazing tutorial thx

[@ArjanCodes]

Glad you liked it!

[@zolika154]

You’re going to be a channel with many subs ! Mark my words.

[@brettbyrnes577]

Nice video! I’m subscribed now!

[@ArjanCodes]

Awesome! Thank you!

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Thanks!

[@ArjanCodes]

Welcome!

[@larrypozdeev]

Great content!

[@ArjanCodes]

Thank you Larry, glad you liked it!

[@immanuelsuleiman7550]

very cool thank you for sharing

[@ArjanCodes]

Glad you like it!

[@TueChristensenDK]

Very nice video, good explanations and well produced. When I see something like the frozen=True colliding with the __post_init then I get sad.... Coming from Java+lombok I am however, not really impressed with this dataclass annotation, but it did improve my knowledge of Python :) Keep the videos coming!

[@maxpfeiffer4135]

Awesome video, thx. That's so damn useful.

[@ArjanCodes]

Glad you liked it, Max - thank you!

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That HHKB. Typing was so fast and smooth.

[@ArjanCodes]

It's a Keychron K2. Feels great.

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Good twist at the start

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Why did I take so long to discover this channel? True goldmine of knowledge. Hit the bell.

[@ArjanCodes]

Thank you Lean, glad you like the content!

[@nardu]

"All your Data are belong to us" 🤣 +1 Arjan, love the Easter egg word portraits

[@BiGreDNoSecoMpAny]

loved Empire Earth as well xD

[@joshcousins9422]

Such awesome content, this video got me to start learning python and I'm loving it! Big request though, could you do a video about Flask? Would be much appreciated!

[@ArjanCodes]

Thank you Josh - it’s on the list 😉.

[@peitlijozsef]

@@ArjanCodes I hope with Dash...

[@aadithyavarma]

@@ArjanCodes Can you compare Flask with FastAPI too? Seems like FastAPI is faster and is more pythonic in way, but I am unsure of the drawbacks of choosing FastAPI over Flask. Can you share your thoughts?

[@lugardjulien5326]

I've learn something , thanks

[@ArjanCodes]

Glad to help!

[@marcello4258]

bedankt!

[@ArjanCodes]

Graag gedaan!

[@Ezechielpitau]

very clear, good length, witcher references. what's not to like? subscribed :)

[@ArjanCodes]

Welcome aboard!

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Oh my, that is a great product! I wish there was a way to pre order it though... It seems to ve impossible atm🤔

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Good keep going 👍